A large brass and glass needle filled with a waxy yellow liquid. As an action, the needle can be stabbed into the heart of a downed player.
This action resets any death saving throws the character had made, places their HP back to max, resets any used mana, and resets any used ability resources (Like Rages or Ki). To put simply, the player gains all the benefits of a long rest. The adrenaline shot removes any: Blindness, Deafness, Paralysis, Stunned, and Poisoned. The character will still be prone after this revival.
The Adrenaline courses through the character's body, removing all caution. The Adrenaline only lasts for 3 rounds, the first starting when on this player's turn. The effect ends after the player finishes their 3rd turn.
The character falls back to their Pre-Adrenal state after the 3 rounds is over, knocked unconscious and back at 0 HP. They start their unconsciousness with 2 successful death saving throws and 2 failed death saving throws.